Lithium borohydride → tert-butyl {(1R)-2-hydroxy-1-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl]ethyl}carbamate

HRID 724599Notes

Reaction equation

HRID 724599 reaction equation
[C:1]([O:5][C:6]([NH:8][C@H:9]([CH2:14][C:15]1[CH:20]=[CH:19][C:18]([B:21]2[O:25][C:24]([CH3:27])([CH3:26])[C:23]([CH3:29])([CH3:28])[O:22]2)=[CH:17][CH:16]=1)[C:10](OC)=[O:11])=[O:7])([CH3:4])([CH3:3])[CH3:2].[BH4-].[Li+]>O1CCCC1>[OH:11][CH2:10][C@H:9]([NH:8][C:6](=[O:7])[O:5][C:1]([CH3:4])([CH3:3])[CH3:2])[CH2:14][C:15]1[CH:16]=[CH:17][C:18]([B:21]2[O:25][C:24]([CH3:26])([CH3:27])[C:23]([CH3:29])([CH3:28])[O:22]2)=[CH:19][CH:20]=1

Participants

4

Reactant 2

HCID 4148881Lithium borohydrideHCID 57581673methyl (2R)-2-{[(tert-butoxy)carbonyl]amino}-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]propanoate

Product 1

HCID 86602075tert-butyl {(1R)-2-hydroxy-1-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl]ethyl}carbamateYield 100%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
0 °C

Procedure

Methyl (2R)-2-[(tert-butoxycarbonyl)amino]-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]propanoate (9.50 g, 0.0234 mol) was dissolved in tetrahydrofuran (30 mL, 0.37 mol) and cooled to 0° C. 2 M lithium tetrahydroborate in tetrahydrofuran (12.0 mL) was added over 3 minutes. The reaction was allowed to stir in the ice bath for 21 minutes. The bath was removed and the reaction continued stirring for additional 3 hours. The reaction was quenched with saturated aqueous ammonium chloride. The mixture was extracted with ethyl acetate. The combined organic extracts were washed with brine and dried over Na2SO4. The solution was filtered through a glass frit and the solvent concentrated to give a white solid (8.80 g, 100%). 1H NMR (400 MHz, CDCl3): δ 7.75 (d, J=8.8 Hz, 2H), 7.23 (d, J=8.8 Hz, 2H), 4.73 (br s, 1H), 3.86 (br s, 1H), 3.66 (m, 1H), 3.54 (m, 1H), 2.87 (m, 2H), 1.42 (s, 9H), 1.34 (s, 12H).

Workup

  1. customThe bath was removed
  2. customThe reaction was quenched with saturated aqueous ammonium chloride
  3. extractionThe mixture was extracted with ethyl acetate
  4. washThe combined organic extracts were washed with brine
  5. dry with materialdried over Na2SO4
  6. filtrationThe solution was filtered through a glass frit
  7. concentrationthe solvent concentrated

Sources & evidence

ORD record
ord-42e3ff9810f74a5f92cf5ce06dba230c
Source dataset
uspto-grants-2006_11
Patent number
US07141596B2

Reaction notes

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